DE29502296U1 - Coil with an elliptical iron core - Google Patents

Description

85G3Q61

Description

Coil with elliptical iron core

The invention relates to a coil, in particular for a magnet system, with an iron core surrounded by a winding.

Such coils are state of the art and are generally known to those skilled in the art. In principle, a distinction is made between the coils shown in FIGS. 1, 2 and 3. FIG. 1 shows a coil design with a round iron core, FIG. 2 with a rectangular core and FIG. 3 with a rectangular core with rounded corners. The following parameters are usually specified for the design of the magnet system:

- a maximum permissible power of the coil

• a pulling force to be provided

• lowest possible copper weight
20

In addition to the further objective of using as little copper weight as possible for the coil winding, the installation space available for the coil can be an important selection criterion.

In order to achieve a given tensile force, a minimum iron cross-section is required in the magnetic circuit, taking into account the saturation limit of iron. With a constant winding width, constant iron cross-section and constant 0 conduction of the coil, the copper weight only depends on the circumferential shape of the iron cross-section. In general, the ratio of area to circumference is greatest for a circular shape and smallest for a flat rectangular shape. A rectangular core with rounded corners has a better ratio with a lower copper requirement than a plain rectangle. The round core requires the same requirements.

95 G 3 fl ß 1

requirements for the magnet system according to the table below, the lowest copper requirement, i.e. it has the smallest copper weight G. The meaning of the abbreviations given in the table can be seen in FIG 5, which shows the cross section of a coil with a rectangular iron cross section. This clearly shows a bulging of the coil winding, i.e. it is not at a fixed distance from the rectangular core along the long sides, but there is a difference between the calculated winding height hr and the practical winding height hp.

Short term. designation Round core Rectangle-
kem German Law
corner core Elliptical core Iron cross section A ^mm2 100 100 100 100 Iron dimensions x/y mm/mm approx. 11.3 5x20 5 x 20.7 R2 Ellipse 5.8 x 22 Distance between iron + copper C mm 1.5 1.5 1.5 1.5 Wrapping width b mm 31 31 31 31 Performance P W 5 5 5 5 Circumference in the coil base II mm 44.87 59.4 57.4 56.2 Winding height right Mr mm 8.3 9 9 8.9 Changing height practical. hp mm 8.3 9.5 9.5 8.9 Total winding width Xw mm 30.9 27 27 26.6 Copper weight G G 95.1 137 129 122

The invention is based on the object of creating a rectangular coil of the above-mentioned type which, with given performance characteristics, in particular maximum permissible power and required tensile force of the coil as well as a certain iron cross-section, has the lowest possible copper weight.

According to the invention, this is achieved with a coil having the features according to claim 1. This has an iron core whose circumference is elliptical.

S 3 O 6 1

The production of the iron core is advantageously based on a sintering process.

Some embodiments of the invention are explained in more detail below with reference to a drawing. They show:

FIG 4 a rectangular coil with elliptically shaped iron core,

FIG 6 an iron core of a coil, the circumference of which is adapted to the elliptical shape by circular segments ,

FIG 7,8 Iron cross-sections with a circumference adapted to the elliptical shape by straight sections and circular sections.
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FIG 4 shows a rectangular coil 1 with an iron core 2, the circumference 4 of which is elliptically shaped. The coil winding 3 indicated by lines fits snugly against the iron core with this shape without bulging. This in turn means that the space surrounding the coil winding 2 is optimally filled with iron and thus used magnetically. Shapes adapted to the elliptical shape, as shown in FIGS 6, 7, 8, are also part of the scope of the invention. In these, the exact ellipses are shown by dot-dash lines and the adapted shapes are drawn as solid lines.

The shape adapted to the elliptical shape in FIG 6 has a circular shape with a small radius at the long ends and a circular shape with a large radius in the narrow area. The contour runs in a straight line between these circular areas. The adapted shape according to FIG 7 differs from this essentially in that the iron core in the narrow area also has straight contours that run parallel to each other, with the transitions being angular. The transitions to these parallel contours run in the adapted shape according to

35 β 3 O 8 1

FIG 8 curved. The end areas are each formed with two circular contours.

These are just a few examples of shapes adapted to the elliptical shape. Generally speaking, adapted shapes are those that deviate from the elliptical shape, with common contact points in the end areas and in the narrow area, by no more than a maximum of 10% of the longitudinal extent of the elliptical shape.

In this way, rectangular coils can be created which, given limited space, ensure the required magnetic flux in the iron core and the resulting pulling force. The problem solved in this way occurs particularly in small-scale contactors. However, applications of the invention described above are also conceivable outside of this specific technical area when using coils in general.

Claims (3)

95 6 3 O 6 1 Protection claims 1. Coil (1), in particular for a magnet system, with an iron core (3) which is surrounded by a winding (2) and has an elliptical circumference (4). 2. Coil according to claim 1, characterized in that the production of the iron core (3) is based on a sintering process. 3. Coil according to claim 1 or 2, characterized in that the circumference (4) of the iron core is adapted to the elliptical shape.